# [MCQ] The Kinetic Theory of Gases MCQ | kinetic theory MCQ

## [MCQ ] The Kinetic Theory of Gases MCQ | mcq on kinetic theory of gases and radiation

#### [MCQ ] The Kinetic Theory of Gases MCQ | mcq on kinetic theory of gases and radiation

i) In an ideal gas, the molecules possess
(A) only kinetic energy
(B) both kinetic energy and potential energy
(C) only potential energy
(D) neither kinetic energy nor potential energy
Solutions :
(A) only kinetic energy

iii) If pressure of an ideal gas is decreased by 10% isothermally, then its volume will
(A) decrease by 9%
(B) increase by 9%
(C) decrease by 10%
(D) increase by 11.11%
Solutions :
(D) increase by 11.11% [Use the formula P1V1 = P2V2. It gives V2V1 = 10.9 = 1.111 ∴ V2V1V1 = 0.1111, i.e., 11.11%

iv) If a = 0.72 and r = 0.24, then the value of tr is
(A) 0.02
(B) 0.04
(C) 0.4
(D) 0.2
Solutions :
(B) 0.04

v) The ratio of emissive power of a perfect blackbody at 1327°C and 527°C is
(A) 4 : 1
(B) 16 : 1
(C) 2 : 1
(D) 8 : 1
Solutions :
(B) 16 : 1

### mcq on kinetic theory of gases and radiation | The Kinetic Theory of Gases MCQ |

The V of gas molecules is 300 m/sec. If its absolute temperature is reduced to half and molecular weight is doubled the V will become:
1. 75 m/sec
2. 150 m/sec
3. 300 m/sec
4. 600 m/sec
Option 2 : 150 m/sec

The molecule of a monatomic gas has only three translational degrees of freedom. Thus, the average energy of a molecule at temperature 'T' is ____________.
1. 3kBT
2. (3/4) kBT
3. (1/3)kBT
4. (3/2)kBT
Option 4 : (3/2)k T

Question: Kinetic theory of gases provide a base for
a) Both Charle’s law and Boyle’s law
b) None of these
c) Boyle’s law
d) Charle’s law
Solutions : Both Charle’s law and Boyle’s law

Question: When do real gases approach the ideal gas behaviour ?
a) At low pressure and high temperature
b) At low pressure and low temperature
c) At high pressure and high temperature
d) At  high pressure and low temperature
Solutions : At low pressure and high temperature

Question: When a gas is in thermal equilibrium, its molecules
a) have the same average kinetic energy of molecules
b) have different energies which remain constant
c) have a certain constant energy
d) do not collide with one another
Solutions : have the same average kinetic energy of molecules

Question: Molecules of a ideal gas behave like
a) perfectly elastic rigid sphere
b) perfectly elastic non-rigid sphere
c) inelastic non-rigid sphere
d) None of these
Solutions : perfectly elastic rigid sphere

Question: In kinetic theory of gases, it is assumed that molecules
a) have same mass but negligible volume
b) have different mass as well as volume
c) have same volume but mass can be different
d) have same mass but can have different volume
Solutions :  have same mass but negligible volume

Question: The internal energy of a gram-molecule of an ideal gas
depends on
a) pressure alone
b) volume alone
c) temperature alone
d) both on pressure as well as temperature
Solutions : pressure alone

Question: The phenomenon of Browninan movement may be taken
as evidence of
a) kinetic theory of matter
c) corpuscular theory of light
d) photoelectric phenomenon
Solutions : kinetic theory of matter

Question: According to kinetic theory of gases, at absolute zero
temperature
a) molecular motion stops
b) liquid hydrogen freezes
c) water freezes
d) liquid helium freezes
Solutions : molecular motion stops

Question:  At a given temperature the force between molecules of a
gas as a function of intermolecular distance is
a) first decreases and then increases
b) always increases
c) always decreases
d) always constant
Solutions : first decreases and then increases

Question: For Boyle’s law to hold, the gas should be
a) perfect and of constant mass and temperature
b) real and of constant mass and temperature
c) perfect and constant temperature but variable mass
d) real and constant temperature but variable mass
Solutions : perfect and of constant mass and temperature

Question: Boyle' law is applicable for an
a) isothermal process
b) isochoric process
d)isobaric process
Solutions : isothermal process

Question: The deviation of gases from the behaviour of ideal gas is due to
a) attraction of molecules
b) absolute scale of temp.
c)  covalent bonding of molecules
d) colourless molecules
Solutions : attraction of molecules

Question:  What will be the ratio of number of molecules of a monoatomic and a diatomic gas in a vessel, if the ratio of their partial pressures is 5 : 3 ?
a) 5 : 3
b) 3 : 5
c) 3 : 1
d) 5 : 1
Solutions : 5 : 3

Question: Assertion: On reducing the volume of the gas at constant temperature, the pressure of the gas increases.
Reason: It happens because on reducing the volume, the no. of molecules per unit volume increases and as
a result more collisions with walls exert greater pressure on the walls.
a) Assertion is correct, reason is correct; reason is a correct explanation for assertion
b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
c) Assertion is correct, reason is incorrect
d) Assertion is incorrect, reason is correct.
Solutions : Assertion is correct, reason is correct; reason is a correct explanation for assertion

Question:  If the pressure and the volume of certain quantity of ideal gas are halved, then its temperature
a) becomes one-fourth
b) is halved
c) remains constant
d) is doubled
Solutions :  becomes one-fourth

Question: Assertion : A gas can be liquified at any temperature by increase of pressure alone.
Reason : On increasing pressure the temperature of gas decreases
a) Assertion is incorrect, reason is correct
b) Assertion is correct, reason is incorrect
c) Assertion is correct, reason is correct; reason is nota correct explanation for assertion
d) Assertion is correct, reason is correct; reason is a correct explanation for assertion.
Solutions :  Assertion is incorrect, reason is correct

Question:   If the critical temperature of a gas is 100ºC, its Boyletemperature will be approximately
a) 337.5ºC
b) 500ºC
c) 33.3ºC
d) 1000ºC
Solutions : 337.5ºC

Question:  A vessel has 6g of hydrogen at pressure P and temperature 500K. A small hole is made in it so that hydrogen leaks out. How much hydrogen leaks out if the final pressure is P/2 and temperature falls to 300 K ?
a) 1g
b) 4g
c)  3g
d) 2g
Solutions : 1g

Question:  If the intermolecular forces vanish away, the volume occupied by the molecule contained in 4.5 kg water at standard temperature and pressure will be given by
a) 4.5 litre
b)5.6 litre
c) 11.2 litre
d) None of these
Solutions : 4.5 litre

Question:  A balloon contains 1500 m of helium at 27 C and 4 atmospheric pressure. The volume of helium at – 3 C temperature and 2 atmospheric pressure will
a) 2700 m
b) 1900 m
c)  700 m
d) 1500 m
Solutions : 2700 m

Question: A perfect gas at 27°C is heated at constant pressure so as to double its volume. The final temperature of the gas will be, close to
a) 327°C
b) 200°C
c) 54°C
d)300°C
Solutions : 327°C

Question: Ratio of volume occupied by a gas H of mass 22 gm at two different pressure p and 2p if temperature remains constant is
a) 2 : 1
b) 1 : 4
c) 4 : 1
d) 1 : 2
Solutions : 2 : 1

Question: P, V, T respectively denote pressure, volume and temperature of two gases. On mixing, new temperature and volume are respectively T and V. Final pressure of the mixture is
a) 2P
b) zero
c) P
d) 3P
Solutions :   2P